1. Field of the Invention
The present invention relates to a blade end portion protecting bag for protecting a blade end portion in installing the rotor for a wind turbine, and a rotor installing method for installing the rotor to a nacelle with the rotor end portion protecting bag fit onto the rotor.
2. Description of the Related Art
Generally, a wind turbine generator includes a rotor equipped with blades to be rotated, a nacelle for accommodating a generator and the others, and a tower for supporting the nacelle.
When building a wind turbine, the rotor is hoisted to the position of the nacelle by a crane to install the rotor equipped with the blades to the nacelle. In this hoisting operation, there is some fear that the rotor equipped with the blades cannot stabilize its position because of the wind. Therefore, it is necessary to pull the blade end portions or the like via a rope in order to control the position of the rotor. The patent publication 1 is well known as a sample in which such position control of blades is performed by pulling the blade end portions via cable.
FIG. 6 shows a lifting state of blades of a wind turbine, which is shown in FIG. 8 of the Patent Publication 1 (Japanese Unexamined Patent Application Publication No. 2005-320919).
FIG. 6 shows a state in which the blades are lifted in substantially vertical direction by a crane so that the blades stand. When an attaching face 032 of a rotor head 03 is attached to an attaching face 034 of a nacelle 033 which is provided on the top of a tower 022, the top of the rotor head 13 is hoisted by a hoist cable 019 of a crane 025. Drawing force is applied to the rotor using the other drawing ropes 029, 031 to control the position of the rotor until the blades stand in substantially vertical direction, while the rotor is hoisted by the wire 019 of the crane 025 and a hoisting wire 028 of a crane 024, thereby standing the rotor in substantially vertical direction (A state shown in FIG. 6). Further, drawing force is applied to the rotor using the ropes 029, 031 to control the position of the rotor, until the attachment face 032 of the rotor is attached to the nacelle 034.
The technique disclosed in the Patent Publication 1 does not specify a method for fastening the ropes 029, 031 to the blade ends. In assembling the wind turbine, there is some fear that the blades may be damaged according to a method for holding the blade end portion or a method for drawing the ropes because the rear edge portion of the blade end portion is thin. Since it is impossible to fasten the rope directly to the blade end portion, the end bag 10s as shown in FIG. 5 is fitted onto the blade end portion.
In FIG. 5, the end bag 10s, which is made from a relatively soft material having high tension and oil resistance such as hemp material, etc., is fit onto the blade end portion of at least one blade 8, which is selected from the plurality of the blades 8, in a predetermined length from the end of the blade 8.
Rope joints 21a are sewed to a portion of an overlapped face 21c in the end bag 10s, and ropes 22 for applying drawing force to control the position of the blades are connected to the rope joints 21a. 